PON Bandwidth Allocation via Two-Level Scheduling
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Solution Overview
Problem
Existing PON bandwidth allocation methods fail to ensure fair access and quality of service (QoS) among different traffic flows, leading to network congestion and insufficient services, especially when the load is heavy, as they are based on service classes rather than individual flow requirements.
Innovation Solution
Implementing the Integrated Service (IntServ) model in the ONU to classify, shape, and schedule traffic, with three service classes (guaranteed, controlled-load, and best effort) and using a two-level scheduling mechanism with weighted fair queuing (WFQ) and token bucket algorithms to manage bandwidth and delay for each flow, ensuring absolute QoS assurance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If bandwidth is scheduled within ONU based on service class, then implementation is simple, but fair access among different traffic flows cannot be guaranteed
Solution Approach 1:
The patent segments the bandwidth allocation process into two distinct levels: (1) OLT performs flow-level bandwidth allocation among individual traffic flows from different ONUs, and (2) ONU performs service class-level bandwidth allocation among different service classes. This segmentation allows each level to operate independently with appropriate granularity, achieving both fine-grained flow control and simplified service class management.
Solution Approach 2:
The patent introduces a new dimension to the traditional bandwidth allocation by adding flow-level control as an additional layer above service class allocation. Instead of only allocating bandwidth at the service class level within ONU, the system now allocates bandwidth at the flow level at OLT, then at service class level at ONU, creating a two-dimensional allocation space that simultaneously achieves fairness and simplicity.
2Productivity
If DiffServ model is used to group traffic into priority classes, then network data transmission rate is improved, but QoS of each traffic flow cannot be ensured
Solution Approach 1:
The patent segments the QoS guarantee mechanism into flow-level QoS parameters (bandwidth, delay, jitter) allocated by OLT and service class-level QoS parameters allocated by ONU. This segmentation enables individual flow QoS to be guaranteed at the OLT level while maintaining the efficiency benefits of service class grouping at the ONU level.
Solution Approach 2:
The patent applies preliminary action by having OLT perform flow-level bandwidth allocation and QoS parameter configuration before traffic enters the ONU. This preliminary flow-level allocation ensures that each traffic flow receives appropriate QoS guarantees before being aggregated into service classes, preventing any single flow from monopolizing bandwidth.
3Adaptability or versatility
If some applications increase data transmission amount, then their bandwidth needs are met, but other normal data flows cannot get services
Solution Approach 1:
The patent implements feedback mechanisms where ONU reports bandwidth usage and queue status to OLT, and OLT adjusts flow-level bandwidth allocation accordingly. This feedback loop enables the system to detect when a single flow is consuming excessive bandwidth and reallocate resources to ensure service availability for all flows, maintaining both adaptability and reliability.
Data Source
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AI summary
The present disclosure provides a system and method for allocating bandwidth in remote equipment on a passive optical network (PON), wherein the system includes an optical line terminal (OLT), which monitors the acceptance of traffic requesting the PON remote equipment for service and configures through signaling control the parameters for the operation of classifying, shaping, and scheduling the traffic in the remote equipment, and a remote equipment which classifies, shapes, and schedules the accepted traffic based on the parameters configured by the OLT and allocates a proper bandwidth to the accepted traffic, and outputs the traffic in the scheduled order. The present disclosure helps ensure the bandwidth and delay requirements of individual traffic flows in the PON remote equipment are met and interaction between traffic of the same or different service class groups is eliminated.